COFFEE LEAF DISEASE 231 



spores develop on the leaves. The two latter often form 

 myriads of little pustules which cause the leaves to fall 

 early, and thus the development of fruit is checked. 



PREVENTIVE MEANS. Spraying with potassium sulphide 

 solution, if commenced sufficiently early, might be bene- 

 ficial, although I am not aware of its having been tested. 

 Fallen leaves bearing teleutospores should be gathered and 

 burned. 



COFFEE LEAF DISEASE 



(Hemileia vastatrix, Berk, and Broome.) 



This terrible scourge, which was first observed in small 

 quantity on a single estate in the Mandulsima district, 

 which occupies the south-western portion of the hilly 

 country of Ceylon, is now widely distributed India, 

 China, Malay Peninsula, East Indies, Philippines, Natal, 

 German East Africa, and probably wherever coffee is 

 cultivated in the Old World. 



The leaves are most frequently attacked, spots being 

 also sometimes present on young shoots and even on the 

 fruit. 



On the leaves the earliest stage of the disease is indicated 

 by the presence of more or less circular, discoloured spots. 

 These continue to increase in size for some time, retaining 

 their irregularly circular outline, become pale yellow, and 

 studded with bright yellow clusters of spores, which soon 

 change to a bright orange colour. The patches show on 

 both surfaces of the leaf, but the spores are confined to the 

 under surface. 



The spores are produced in dense clusters on the tips 

 of hyphae which come to the surface of the leaf through 

 the stomata. Those surfaces of the spore that are in con- 



